The art is cognizant of applying insulation for the roof of a metal building from above, before the roof sheets are installed. Alderman, U.S. Pat. No. 4,147,003, shows the placing of insulation in a trough of flexible sheet material formed between adjacent purlins of the roof and supported by a lattice of support straps, including support straps that extend between the purlins and through holes previously created in the purlins, or rest on rafters supporting the purlins. Alderman also shows the placement of insulating material over the tops of the purlins before the roof sheets are fastened to them. Related patents to Alderman include U.S. Pat. Nos. 3,559,914; 3,969,863; 4,047,345; 4,047,346; and 4,075,807. Wells, U.S. Pat. No. 4,117,641, shows clips adapted to be hooked to the lower stiffener members of purlins having a "C" or "Z" cross-sectional configuration. In Wells, an insulating board is engaged in the clip attached to one purlin and extends therefrom to an adjacent purlin to rest on the lower flange of the adjacent purlin. The clip and insulating board arrangement is applied to the purlins from beneath by a worker on scaffolding or the like. Bats of insulation may be carried on the board and held between the board and the roof sheet above.
Interlante, U.S. Pat. No. 4,251,972, shows a panel support merber adapted for use in buildings having roofs supported by purlins. The panel support members extend from the lower flange of a "Z" configuration purlin under the adjacent purlin, to hook back up and over the lower flange of that adjacent purlin. The panel support members again are adapted to be installed from beneath the purlins after the roof sheets are in place.
The art is not cognizant of means for installing a support for insulation from above without the need to modify purlins or other roofing support members so that insulation may be conveniently installed while the roof is being constructed and without the need to erect scaffolding or to subject workers to the discomfort and health hazards of attempting to deal with insulation directly above them as they work on the underside of a roof.